Electric tracer control machine for



Jly 21, 1942. E. R. LocHMAN Re. l22,140

' ELECTRIC TRACER CONTROL MACHINE FOR DIE SINKING AND THE LIKE Original FilAed April 30, 1954 7 Sheets-Sheet l INVENTOR.

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M. m wm July 2l, 1942. E'. R. LOCHMAN ELECTRIC TRACER CONTROL MACHINE FOR DIE SINKING AND THE LIKE Original Filed April 30, 1934 7 Sheets-Sheet 2 INVENTOR.

uml! ATTORNEYS July 21, 1942 E. R. LocHMAN Re. 22,140

ELECTRIC TRACER CONTROL MACHINE FORl DIE SINKING AND THE LIKE Original. Filed April Z50, 1934 '7 Sheets-SheetI 5 l m ATTORNEYS July 21, 1942. E. R. LocHMAN ELECTRIC TRACER CONTROL MACHINE FOR DIE SINKING AND THE LIKE Original Filed April 30, 1934 '7 SheetsSheet 4 INVENTOR.

ATTORNEYS July 2l, 1942. E. R. LocHM AN R 22,140

ELECTRIC TRACER CONTROL MACHINE FOR .DI vSINI'CING AND THE LIKE origina; Filed April so, 1954 7 sheets-sheet 5 lo l l 469 INVENTOR, 475

ATTORNEYS July 21, 1942. E. R. LocHMAN Re. 22,140

A1E`.LEC"lR[C TRAGER CONTROL MACHINE FOR DIE SINKING AND THE LIKE Original Filed April 30, 1954 7 Sheets-Sheet 6 July 21, 1942.

E. R. LOCHMAN ELECTRIC TRACER CONTROL MACHINE FOR DIE SINKING AND THE -LIKE 'T Sheets-Sheet 7 Original Filed April 30, 1954 fcgi ATTORNEYS Reissued July 21, 1942 ELECTRIC TRACER CONTROL MACHINE FOR DIE SINKING AND1 THE LIKE Emil R. Lochman, Milwaukee, Wis.

Original No. 2,254,229, dated September 2, 1941, Serial No. 723,105, April 30, 1934. Application for reissue September 2, 1941, Serial No. 409,319

(Cl. Sil-13.5)

62 Claims.

My invention relates to improvements in electric tracer-control machines for die sinking and the like.

It is the broad object of the present invention to render more delicate, sensitive, and rapid the operation of a machine of the class shown in my Patent No. 1,774,279 granted August 26, 1930. The apparatus disclosed in said patent and in the present application is of such a nature that any pattern, whether of metal or of non-conducting material such as wood, plaster, or the like, may be duplicated.

More specically, the present invention seeks to improve over earlier devices in this art by providing an electrically controlled and preferably magnetically operated brake, the action of which supplements the controls for advancing and retracting the tracing point and tool, the several controls and the brake being subject to intermittent direct electric current which is automatically distributed alternately through the brake and through the actuating controls, so that each controller action is followed by a brake action and vice versa, thus enabling the apparatus to function much more sensitively and with greatly increased speed as compared with any previous device.

A further object of the invention is to utilize the two streams of interrupted direct current alternately at the tracer to sensitize the operation thereof. 1

It is also important that in the present invention I provide mechanical devices subject to vibration as a means of delivering the power of the magnets to the controllers and also to the brake, not only to increase the gripping action of the parts while the intermittent current is effective therein, but also to introduce a periodicity ensuring a prompt release of the gripping action.

A further object of the invention is to provide a connection from the control shaft to the carriage upon which the tracer and tool are mounted, which connection shall be absolutely free of lost motion to promote the greater accuracy and speed. of operation of the carriage.

Another object of the invention is to provide a novel, improved drive for the work support including an automatic control, actuated by an overload circuit, provided in the tracer, for interrupting drive to the work support in the event that the rate of traverse employed is so high that the tracer and tool cannot move sufliciently rapidly to accommodate the drive.

Other objects of the invention include the provision of a novel mounting for the several armature parts of the controllers and brake, all of which are splined upon a gearlike transmitter or mounting carried by the control shaft, the provision of a novel and improved form of rotary interrupter and spark quenching device; the provision of a novel and improved mounting for the carriage upon which the tracer point and tool are disposed, the object being to enable this carriage to move backwardly and forwardly at a touch, to enhance the sensitivity of the machine and its delicateness of operation; the provision of means whereby a central blower system is employed to deliver dust free air to all portions of the machine requiring either cooling or an air blast, whereby tracers and points are protected from dirt which might otherwise be carried to them by such air; the provision of a novel and improved form of armature which will be relatively free of electromagnetic eddy currents and will tend to free itself of dust accumulations without scratching or destroying the coacting clutch plates; and nally, the provision of a new and highly sensitive tracer mechanism in which greater and more delicates response is assured and the arrangement of the tracer lever with respect to the contacts controlled thereby has been reorganized and improved.

In the accompanying drawings in which the same reference characters indicate the same parts in all of the views:

Figure 1 is a side elevation of the diesinking machine showing a side view of the principal features with parts broken away showing operating features located in the base of the machine.

Figure 2 is a side View of the drive for the work support, showing details of the friction drive and the location and connection of the driving motor.

Figure 3 is a plan view of the principal operating features of the machine as mounted on top of the box-like base, with the top beam 2l and its driving features removed, but showing the rear driving pulleys, variable speed motor and its controller.

Figure 4 is a perspective view of the operating mechanism for reversing the drive for the work support, including the solenoid 33S, which is shown electrically connected in Figure 28.

Figure 5 is a plan view of a modified motor for the drive of the work support, showing a, loose pulley and :magnet drive connection.

Figure 6 is a side view and part sectional view of operating mechanism for reversing the drive of the work support automatically by means of solenoids (see Fig. 28).

Figure 7 is a view of a control set E partly in side elevation and partly in axial section, showing the controllers, the brake, the armatures and transmitter,

Figure 8 is like Figure '7, showing a modified electric brake, with its ring-like form fitting over, and being located outside of the control casing 45, and showing the upper part of the supporting frame F in which said parts are operatively mounted.

Figure 9 is a front elevation and sectional view of the electric brake shown in Figure 8, with parts broken away to show a brake vibrator and its co-related parts in operative connection.

Figure 10 is a front View of a section of a controller, with parts broken away, showing4 the location of two magnets in proper relation to the armatures and the transmitter, also showing a, pair of` vibrators.

Figure 11 is a cross section through the. magnets on line lil-I'I' of Figure 10, showing the proper working position of the vibrators in relation to the armatures and the magnet.

Figure 12 is a diametrical section of a controller with" parts broken away, showing the parts for mounting and adjusting the magnets.

Figure 13 is a rearv View of a section of a controller showing the mounting of the magnets with their respective coilsand the. connection of their respective leads.

Figure 14 is a plan View of the current breaker, showing the double air channels leading across the two current breaker disks.

Figure 15 is a vertical cross section in line |5-I5 oi- Figure 14, showing the metal sections and the insulation sections of the current breaker body andy the two air channels leading across the two breaker disks.

Figure 16 is a side view of the current breaker, showing the air supply unit and the breaker unit in working position, with the brushes and respective wire leads.

Figure 17 is a cross section on line I'l-H of Figure 16, showing a fullsize detail of an air channel leading across a breaker disk and showing the mica partitions and lining in front of the brush.

Figure 18 is a cross section on` line IB--I of Figure 3, showing details of construction of the tool carriage, its ballbearing slide and the mounting of the tool casing.

Figure 19 is a sectional side view on line IQ-IS of Figure 3, showing a cross section of the control shaft and spring-band connection to the tool carriage, also the ball slide with its cage and stops.

Figure 20 is a plan view of the tracer with parts broken away to illustrate all of the operating parts in proper working position.

Figure 21 is a cross section of the tracer taken in a manner to fully illustrate the operating parts in their respective relation to each other.

Figure 22 is a plan view of a controller armature.

Figure 23 is a plan view of a brake armature.

Figure 24 is an enlarged detail of Figure 25 showing the armatures and magnet associated with a vibrator in proper working position.

Figure 25 is a cross section through the magnets like Figure 1l, showing, however, the Vibrators mounted on a vibrator cage direct for adjustment unitarily.

Figure 26 is a diametrical section of a controller like Figure 12, but showing the vibrator cage for adjusting the vibrators unitarily with its adjusting nut lill.

Figure 27 is a sectional plan View of the vibrator cage with a pair of vibrators in proper working position with the outer armature, also parts broken away to show details.

Figure 28 is a complete diagram of the electrical connection from the power line to the current breaker, from there to the tracer, and from there to the controllers and the brake, said three parts marked E comprising the control set; also an additional circuit aiecting the work support and connected to the tracer, as well as a separate circuit affecting the reversing device for the work support.

Figure 29 is a side view of a modied driving and reversing device for the work support, modifying like parts as shown in Figure 2.

Figure 30 is a plan view of Figure 29 with arrows showing the magnetic circuit rmly connecting the effective parts for driving and reversing the work support.

Referring now more particularly to the drawings, it will be noted that the essential parts of the machine are marked with capital letters for easy reading of the more complicated assembly drawings, and for the same reason the figuring follows a continuous description of related parts of the machine.

The base of the machine B is of box shape and preferably of welded steel construction which is adaptable for various sizes of machines. The space within the base is used for auxiliary apparatus, while on the table-like top B the principal working elements of the machine are built up.

The frame F is rigidly mounted on the top B of the base with bolts 3 and houses the control set E comprising three principal units, the controller Cl, controller C2 and the brake S. A casing ring is rigidly mounted in the seat 44 of the frame F, and the brake S is fitted with its seating groove E4 to said casing ring 45, and the brake S is rigidly mounted by lugs 66 to the frame F by screws (see Fig. 7). The outer casing ring 4l in turn ts to the ring-like brake S with its seating groove B9, but said outer casing ring 4| is part of the outer frame casting `40 having hinge lugs 61 matching with hinge lugs El of the frame F, all having the bore 68', and said castings are connected for hinge action by the bolt 68 (see Fig.I 7), while the upper lug I4! rmly secures said outer casting 40 to the frame F by the cap screws E42 (see Fig. 8). Thus the control set E forms a drumlike body in its outer appearance as shown in Fig. 3.

The control shaft I has its bearing in sleeve 34 firmly mounted in bore 34' of the frame F which also has a second bearing 42 for said control shaft I, leaving free spaces of said shaft for mounting the spring drums 2, which are rmly clamped to said shaft after the flat ribbon or band springs 3 and 4 have been inserted in a suitable slot and held by screws 2 by cap screws 2'. Said spring drums are made in two halves for clamping (see Fig. 19). The outer ends of said springs are securely fastened to the tension clips 3-4 extending into the hollow beams 'l of the tool carriage A which have lugs 5 and E at the ends through which the tension screws 4 are loosely passed and screwed into said clips for tightening the bands 3 and 4, thus taking up all lost motion between the control shaft and the tool carriage, thereby assuring better finished Work.

The tool carriage A (see Figs. 1, 3 and 19) has a straight vsurface B provided with holes 9 through which the tracer T is held in various adjusted positions, according to size and location of work, by the bolts l0, passed through slots so that the tracer may be set forward or rearward according to the depth or thickness of the pattern 495 and work 406. The tool casing R is also endwise adjustable on the mounting rib |16 (see Fig. 18). The straps I4 hold the casing |11 in adjusted position by tightening the clamping plates i3 against the angles I4 of said Straps, thus clamping the casing to the spacing block |16' by the capscrews I3. The tool spindle |'11 is held in suitable ball bearings in said casing and eX- tends at both ends, carrying the chuck |18 and the cutting tool |19 at the front, and the stepcone pulley I -I6 at the rear end.

The idler I1 is held in running position at the outer end of the bracket'IB having a hinge I9 adjustably held to the tool .carriage A in a manner so it will take up the slack and guide the belt 2| along the driving drum 20 during the forward and rearward motions of the tool carriage, either on step I5 for slower driving or on step I6 for faster driving of the spindle and cutting tool |19.

The variable speed drive for the cutting or grinding tools has 24 variations, ranging from 185 to 8700 R. P. M., thus enabling the machine to be used for a great variety of work not possible with other machines, and made possible by the combination of said drive, where said drum 20 is mounted in parallel alignment with the tool spindle on shaft 22 turning in bearings 23 held adjustably in hangers 49 mounted by lugs 50 to beam 21, being held from endwise motion by set collar 25 and the stepcone 26 having three steps and matching with the three steps of stepcone 28 on variable speed motor 30 supplying four main speeds, which in turn are switched on by turning the crank 32 into steps 33 of controller The outer controller CI has a central bearing 35' by which it revolves on stub shaft 38 rigidly held in hub 33, and -having a conical bore 31 into which the cone pointed end 36 of control shaft I nts and bears. This bearing cone is shaped so that the hinged part Ail-4| together with said controller CI may be swung outward on the hinge holt 53 when any of the `parts of the control set E need adjusting, or for inserting said parts in their respective places, which is done as follows.

Controller C2 with its bearing 35 is passed over the bronze bushing 34 on which it runs, then washer 34 is passed over shaft l', then transmitter '5| is passed on said shaft and rigidly fastened by key 52" and set screws 52, then armature 56 with its internal gear teeth 54 is passed over the gear teeth 53 of the transmitter 5|, both of said gears matching perfectly into each other to prevent lost motion, but allowing sliding or floating motion of the armatures endwise along the length of the teeth, so they may always be held in close sliding contact with the friction surface 14 preferably made of cork.

The vibrator ring 18, (see Figs. 10, l1, 12, 24, 25, 26 and 27) is passed over the transmitter and securely fastened by slotted screws 86) into its seat 39, in a manner such that the vibrators 85 will be held in position as shown in Fig. 11, where said vibrators are held in separate holders for individual adjustment for each vibrator by turning the holder so that the hinge formed by the non-magnetic part 9| with hinge pin 90 is adjusted so that the heel 85 of the vibrator 85 sets against the armature 15 as shown in Figs. 24, 25 and 11, and is then held in said position by tightening the cap screws 83 reaching through holes 33 into said holders 8| (see Fig. 10). The regular adjustment of the entire series of vibrators, of which there are ten pair of twenty single vibrators in each controller in the present machine, is done by adjustably turning the large ring-like nut lill, and when adjusted as shown in Fig. 25,

said ring and nut are held in said position by tightening screws 8U.

The brake S is next passed over the transmitter and held in proper alignment by said groove 64 and held rigidly by said respective screws 65. Then the brake armature 51 is passed over the transmitter; then another vibrator ring, preferably one with individual adjustments for the vibrators, and held in position by screws 8l) in rigid stationary brake position. The brake Si! (see Fig. 8) is like the brake S in all essential features. However, its ring or channel-like body is larger in diameter and is mounted over the outside of casing ring 45 in rigid alignment th'erewith; the solenoid magnet |22 is mounted in the channel |21 of the brake ring, the vibrator ring |39 (see Fig. 9) is rrnly mounted on the brake ring with screws |39', its raised rim having slots |38 through which the vibrators |20 are loosely passed while they are pivotally mounted to adjusting screws |35 and adjusting nuts |34 by pivots |33; the magnet core is loosely passed through the outer free end of the vibrator and inserted into loose sliding contact into th'e liber bushing |26 of the magnet coil |22. The cone and socket joint |23' has a suitable gap, set properly for producing the strongest pull of the core |2| by setting the core plug |23 lengthwise in its bore |24 and holding it rigidly by set screw |25. In said adjusted vibrating position the pin |2|' driven in the outer end of the core |2| is holding the core from turning by the small ribs |20 while pulling the long outer section in vibrating pulls at the rate of about times per second and gripping the armature at the same rate of speed with the shoe |36 held to the inner short section of the vibrator by pivot |31.

It will be noted that the magnetic pull is more than doubled by the lever action of the vibrator against the brake armature 51 with the outer armature |36 (see Fig. 9) to which said brake shoes |36 are attached. It will further be noted that no magnetic flux passes the brake armature 51 in brake S2 which is preferable for some classes of work. The transmitter of said brake is holding the armatures 55, 56 and 51 on pins Ill', and the brake armature 51 is held in-a gap by ring I9 held by screws ||8. The use of pins for holding the armatures has the advantage that for very large control sets said armatures may be made in sections, which are easier to keep straight and hug the friction surface 14 (see Figs. 10, l1 and 24) which is alike for the controllers as well as the brake.

The flange of' the outer casting 4!) forms a channel having bores |65' through which plugs |29 extend and are firmly mounted, same having a bore in which a plunger is inserted for endwise sliding motion and is bearing against the outer end of plunger |2I, against which it exerts Ia light and adjustable spring pressure by spring |3| and adjustable bushing |30 through which the shank |30 passes, and when the parts are adjusted, they are held in position by they set screw |32. The spring pressure of these said parts is transmitted to the brake armature by the vibrators |20.

The armatures 55, 55 and 51 are all alike in their specific construction except certain grooves 5228 cut into the brake armature 51 (see Fig. 23). These vary in their respective angles so they will keep the friction surface clean and smooth and still increase the gripping ability to said somewhat resilient surface 14, preferably made of cork. The controller 'armatures 55 and 55 are alike, and have a slight spiral groove cut into the o-ne lying against the friction surface 14, (see Fig. 22) and running in the direction of arrow 55', which will keep said surface clean by carrying dust, etc., outward in said spiral groove while at the same time increasing the gripping action against friction surface 14, thereby giving greater power to push the cutting tool into steel or other hard material.

The outer armature 15 is made up of sections of easily magnetized sheet iron on whichl the heels 85 of the vibrators rest and through which the horseshoe magnets complete their circuit of magnetic uX by passing through both armatures, then through the vibrators and drawing them inward to said iron sections. These are separated by non-magnetic metal sections 16, preferably die cast right on said iron sections, and providing lugs 11 through which pins 11 pass in sliding it to carry said armature 15 on the vibrator ring 18 or 18 and keep it turning with the controller, but in constant original alignment with the horseshoe magnets as shown in Figs. 11, 24 and 25. It will further be noted that the inner bearing side of armature 15 is lined with a thin layer of friction liber 15' so it will not have a metal to metal contact with the inner armature 55. The armatures have, furthermore, slots 22S at their inner side for the purpose of breaking the magnetic field, thus giving a more powerful grip to the magnets by intensifying the flow of the magnetic Iiux, concentrating same to smaller local sections.

The mounting and adjusting of the magnets in the controllers will now be described. The body of the controller has two outer rims, which are connected with a number of ribs |00 equal in number with the magnets to be inserted (see Fig. so the present controller CI has 10 ribs, thus providing ten equal spaces for inserting horseshoe magnets 58 into the holes 8B bored through the non-magnetic metal ring 13. The wire coils 58 are passed over the respective Shanks of the wire core of the magnet. The rear part of the wire core is held in the crescentshaped groove |50 of block 1|'. Both of said parts are then firmly mounted to the mounting ring 1| by screws 58", the gear rimmed nut 62 forming a large nut fitting the thread 1| of the mounting ring 1| and screwed onto it. Then the entire unit with the magnets in place is set into the position shown in Figs. 11, 12 and 13, so that the magnet cores leave a very slight gap 55' (see Fig. 24). There is no metal to metal contact between said wire core ends and the armature 55. The parts are then locked by the cap screws |02 firmly to the controller body |00. It will be noted that with the entire assembly in place, the vibrators hold the armatures against the friction surface 14 under a slight yielding pressure by springs 86 passed over and mounted on stubs 81 of holders 8| for individual adjustment. Springs 92 (see Figs. 25 and 27) are provided for adjusting the entire series, whereby said vibrators are further held from excessive swinging between the flanges of slot 96 (see Fig. 24).

For the electric connections of the controllers a heavy disk of insulation material |02 is mounted to the inner ribs |02 by screws |02" (see Fig. 13) to which the leads IEM- |08 of coils 50 are secured by the small screw bolts IBS-|03 to which they inner leads INV-|08 are attached, which connect the collector rings It- |01 and brushes IUS-l l0 with wire leads H2, I|3 and ||4 to which the power is supplied. The covers 12 are mounted on the inner face of the controller and same have a deep groove 12 for catching any oil or waste lubrication, so that the friction surfaces and armatures are kept completely dry and clean. The brush holders ||5| I6 are mounted in their respective places against either side of the frame F so the controllers may be inserted or taken out without interfering with the brushes or power Wires. In Fig. 8 certain clamps |43 are shown passed over screw threaded studs |41 and held in adjusted positions of the magnets which they grip by nuts |49, for individual adjustment of said magnets. The outer magnet CI is inserted by opening the outer frame part 40 and inserting the entire assembly of said controller including the armature 55, passing the hub bearing 35 onto the stub shaft 38, then closing said frame part 40 which at the same time brings the said armature 55 with its teeth 54 in contact with teeth 53 of the transmitter 5|, the cap screws |42 keeping said outer frame part in locked position.

The controllers are driven in opposite directions (see Figs. 1, 3 and 13) by pinion |50 mounted on shaft |5|, to which gears |52|53 are connected and running in opposite directions as shown by arrows af-b, said shaft |5| being driven by pulley |54 and belt |56 in bearing bracket |53 mounted on frame F (see Fig. l) and connecting to pulley |55 mounted on shaft- |51 running in bearings 45E-462' and having pulley |59 (see Fig. 3) to which cross belt may be applied for running the controllers in opposite directions.

It will further be noted that the main body of the controller |00 is of cast iron but all the metal parts surrounding the magnets are of non-magnetic metal, this including mounting ring 1|, block 1|', ring 13, the vibrator ring 18 and the vibrator hinges 9|, so that the magnetic ilux is concentrated to the thin armatures and the vibrators, thereby giving these parts the greatest possible magnetic attraction which the rapidly interrupted direct electric current can produce.

The tool carriage (Figs. 13, 19 and l) is mounted for easy sliding motion in straight lengthwise extending ballbearing slides in bars 415 having ball grooves |13|14 in which balls |55 are inserted and are held in position by the spacers |51, which have an extension IEB striking stops |59 set for a certain distance of travel and clamped against the bar |1| mounted parallel with the bearing bars 415 by cap screws I1| but leaving a slot for the thumbscrews VH1-|10 for sliding adjustment for said stops |39. As the tool carriage usually moves only a limited distance back and forth, the ball spacers are set according to said working position. The main bearing bars 415 are mounted on the respective beams 469-410 with screws |12 in parallel alignment with the tool carriage. However, the lugs 41|-412 are provided with set screws 413- 414 (see Fig. 3) to keep said bearing bars 415 in perfect alignment and the ball bearings without any lost motion so that tracer 230 and cutting tool |19 will do perfect work. It will be noted that the spindle casing R is set above a strong rib |15 of the tool carriage, and same carries the steel ball race lining |13 giving strong anti-friction support to the spindle |11 and cutting tool |19 even under heavy side thrust when cutting steel or -other hard materials. My ball race device for straight slides greatly increases the efciency of machines of this type, and is of very important use for easy slide motions of Vheavy work supports.

The current breaker K will now be described (see Figs. 14, 15, 16 and 17). The outer sleeve |80 of suitable bronze has the solid supply flange |80', while the breaker disks |84-|85 at either end have each three equally divided cut-out sections, which, like the core |82, are filled out with a suitable insulation material such as Bakelite, preferably formed in a solid mass with the bronze outer sleeve |80 mounting and insulating said unit on the shaft |8| running in bearings 20| of bracket 202 having arms 200 in which the bar |94 insulated by the ber tubing |95, is solidly held in the bored-out lugs |99 by set screws |98.

Brush holders and brushes |86, |81 and |88, each pair forming one unit and being numbered as units, each have an upward extending arm |91 to which the brush is held in adjustable position by clamp |92 and screw |93, and said units are held in proper position by clamping same to the insulated bar |94 by screws |86. The breaker disks |84-I85 have insulating disks |83 extend-A ing to the outside thereof to aid in cutting the arc. The breaker disk |84 has longer metal sections and supplies its interrupted current to the controllers by way of the tracing wire 290 of the tracer T, while the breaker disk |85 has shorter metal sections and supplies its interrupted current to the brake S, and to the coil 213 of the stop magnet 212 of the tracer T.

These metal breaker sections of said two breaker disks are spaced alternately so when the controller side |94 is on, the brake side |85 is off and vice versa. Thereby the current breaker automatically applies a brake action after each control action to the control set E as well as to the tracer T, resulting in fast and smooth tracing and cutting action of the machine.

Using 220 Volt direct electric current passing through vthe current breaker, the sparking between the breaker sections and the brush is excessive. Therefore a very strong current of air is used to cut oi said spark as follows: The air pipe 203 has a ange 222 and is mounted by suitable bolts on the table B as shown in Figs. l, 3, 14 and 15, so that certain air nozzles 2|8-2I9 are located centrally above and leading across each of said breaker disks. Said air currentis accelerated by reducing it from a 2 pipe to two 1/4 x 1/2 iiat nozzles which are again subdivided each in two separate 1/4 X 1/4 nozzles by the mica partition 2|3 which, with two side partitions 2|5 and 2|6 and a top sheet 2|| having a slot 2|4 fastened with screws 2|2 into the reducing channel 204 of insulating block 208, form a perfect mica lining for said nozzles having slots 2|4, 2|5 and 2|6 into which said mica p-artitions are inserted, set down to the surface of the breaker disc and clamped in said position by screws 2|1 (see full size detail view Fig. 17

showing one of said nozzles with the current flowing in the direction of arrow and the breaker disk running in the same direction, while the air is flowing in the direction of arrows g-h). The block 208 has reduced sections 209 into which openings 2|0 are cut, for clear observation of the spark cutting action o1' the air currents flowing through said nozzles, leaving a third open section 220 for the same purpose. A small section of mica is formed at the three ends of the metal sections into each breaker disk to prevent the arc from burning the insulation at these points. The arc is the hottest when said respective metal sections leave the brush, and the arc is blown out by the strong air currents forced through said nozzles 2|8-2|9. While each breaker disk has three equally divided metal sections, these sections are longer in the control disk |84, and about one third shorter in the brake disk |95, thus giving the controller magnets 58-59 a longer, and the brake magnets 60 (see Fig. 7) a shorter time to act on their respective armatures, resulting in fast and accurate tracing and cutting action of the machine.

The air pipe 203 turns and tapers in its upper right angle turn, and forms into a right angular shape, of which the reducing channel 204 of block 208 forms the continuation. The upper end of said air pipe forms into the straight ange 22|, having the outline of block 208, and on which said block is mounted by screws 2|1, which also hold the cover 201 having an inward curved section 201' covering and leading the air stream in the opposite directions of arrows g-h (see Fig. 17). Said block 208 has downwardly extending sections 2|0 overhanging the sides of said breaker disks and forming the bottom of said air nozzles 2|8-2|9. Said air pipe 203 has another pipe 205 leading off in an upward direction, and the tracer tube 206 preferably of rubber is attachedto the nipple 205 while the other end of said tube is attached to the nipple 291 of tracer T (see Figs. 1 and 2l), and the upper loop of it is supported by the hook 205.

The current breaker K has a step cone 224 matching with the step cone 225 on shaft |51, and is driven at various speeds according to the respective Work by belt 22B, preferably at 60 breaks per second.

The tracer T (see Figs. l, 3, 20 and 2l) will now be described. The tracer point 230 is of various forms according to the size and shape of the cutter, but the one shown is a certain standard shape and used extensively for various kinds of work. Said tracer point 230 follows the pattern, while all the other apparatus forms a guiding and control device for operating the control set E, which in turn controls the forward and rearward motions of the tracer and cutting tool, with the object of using a plaster, wood, or other inexpensive pattern against which the tracer operates with a light pressure of about one half pound to one pound, while at the same time the cutting tool operates with from to 200 pounds of pressure for cutting into hard steel, etc., which pressure varies according to the size and gearing of the control set E to the tool carriage.

The bored and tapped end 23| of the tracer 230 fits to the screw 232 of the tracer bar 2110 and is screwed tight against shoulder 232. The universal action of the tracer 230 to operate the contact 283 is caused by the ball 233 and socket joint 235 of chuck 235 seated tight against shoulder 238 of barrel 268 and bushing 239, but leaving a small gap between the shoulders 2332-238 of said parts for a slight end motion of said tracer for operating said contact 283.

A hole in the wall of chuck 235 through which a small screw 234 is passed and set into the ball 233, is for the from turning when tracers are screwed on and off said shank. However, clearance is provided for said screw 234 as well as for the shoulder 23 I to allow for free action for said universal joint. The hard steel bushing 239 is fitted and screwed tight into the barrel 268 by its screw threaded end 252. The finished bore 248 receives two steel balls 248 which are seated into the countersinks 241-258 of the shank 248 and the plunger 25| having a coil spring 253 pressing against the shoulder of said plunger and being stripped over the plunger rod 254 with its pointed top end seated in the cone socket 255 of adjusting screw 256, held by its nut in its adjusted position. While one of said balls 249 is suflicient to connect the respective parts for operating the controller contacts 284-235, the resiliency of two hardened steel balls 249 against each other and co-acting with the tracer point 23|) forms a distinct improvement in sensitive tracing action of the machine. The outer end of spring 253 bears against the clip 283 having a slot for adjusting the pressure of said spring and held in proper adjusted position by screw 264.

The contact frame 285 operating on the pivot 266 has the angle 258 operating on pivot 251 with its outer free shank against the lining 259 on the inner side of said open contact frame, ywhile opposite thereto the adjustable spring 483 held in the bore of adjusting screw 482 bears against said frame, said screw being held by the .screwy threaded lug 484 for pressing the frame and contact 283 over against contact 284 connecting with controller CI. At the same time magnet 219 is energized by the same current from the controller disk `|84 and draws said contacts tight for positive controller action, which again is relieved periodically by magnet 212 drawing the ball 219 in its cone socket, thereby holding the contact 283 neutral between the controller contacts 284-285, thus causing a brake action between each controller action, for accurate tracing action of the machine.

When the pattern in its feed motion strikes the tracer, then the contact 283 is pushed over to control contact 285 connecting to the from Work controller C2 and the tracer and tool are drawn away from the pattern. It will be noted that these vibrating` actions of the tracer contacts follow each other 60 times a second, causing fast and accurate tracing and cutting action of the machine, of which the only mechanical action is caused by the striking of the pattern 405 against the tracer 280, while all other actions of the tracer are caused automatically by the automatic distribution of the rapidly interrupted direct electric current, coming from the current breaker, and going into the combination circuits of the controllers CI-C2 combined with magnet 219, and into the brake circuit S combined with the neutralizing magnet 212.

These actions of the respective controllers and the brake are greatly intensified by the actions of the vibrators, also caused by said interrupted current. Said angle 258 operates on pivot 251 held by adjustable block 268 by screws 26|. Said block may be adjusted in threaded holes 262, and a longer free shank angle 258 shown in dotted lines may be used, for finer action, with less side motion of the tracer point. Thus the tracer T purpose of keeping the shank 240 may be readily adjusted for various classes of work, while the alignment of the contact frame 265 and the respective contacts remains the same.

The drawings show an excessive gap between said contacts for easy reading of the drawings, while in actual practise these contacts are set less than 1,64 of an inch apart. The spark being killed at the current breaker, no sparking takes place at the changing or operating between the contacts, which is another great advantage of my system of using said interrupted current. The closer the contacts can be set, the Vless motion is required of the tracer point for operating same and the more accurate the pattern will be copied. The entire tracer casing as well as the contact frame 265 are made of a light Weight aluminum casting, and a hardened and ground bushing 269 is inserted for a sliding rit of ball 21|) which, by being drawn into its cone-shaped socket 21| of magnet 212, holds the contact 283 central and out of contact with said other contacts as shown in Figs. 20-21 when the brake acts to keep the tool carriage from moving, which action takes place 60 times a second, and continuously keeps said position when cutting and tracing a straight surface.

It will be' understood that continuous movements of the tracer, such as by the described vibrating means, are of utmost importance in increasing the sensitivity and accuracy of copying, both of which depend upon relative movement of the tracer parts between positions effective respectively for forward or in movement of the tracer toward the pattern, and for interrupting such forward movement. If the tracer parts are permitted to come to rest between the control movements thereof the various pivots and other friction surfaces involved become subject to the friction of rest, or static friction, which is not only high as compared to the friction of a body already in motion, but is also variable according to variations in, for example, temperature, lubrication, the condition and fit of the surfaces, etc. In the present device there is no static friction by reason of the vibration and the continuously moving tracer points are operative under the control of the pattern with very much less pressure, and` the pressure required does not vary, remaining substantially constant under wide differences of operation conditions such as just mentioned. However, such continuous motion of tracer electric contacts might give rise to increase of sparking or arcing between the contacts. This is avoided in the present device by the use of divided or intermittent current applied as herein described in such manner that no voltage differential exists between the tracer contacts at any time when the vibrating mechanism opens the contacts.

The tracer T, on account of its co-acting magnets automatically vibrating its contacts, except when the mechanical action of the moving pattern striking the tracer is operating same, or when the tracer being away from the pattern, is operated by spring 483, which of course is always` acting to push contact 283 over to Contact 284, but is constantly assisted therein by magnet 219 attracting the small armatures 218, but always leaving an air gap. Said magnet is rigidly mounted on the casing by the grooved block 282 and screws 28|, and the front by the clip 280 and its screws holding the coils 288 in place, while its respective leads 216--211 are connected as shown in Fig. 2'8, which further illustrates the action of the tracer parts and the insulation of its contacts.

The tracer T has a chamber 296 for receiving coil 213, and suitable wiring for its various electric connections. A bottom 309, ypreferably of insulating material, is fastened by screws 3|0, and a transparent cover 304 is held in frame 303 by clips 305 and screws 306, said frame being removably held by groove 302', fitting over ledge 30|, and a loop 301 fitting over flange 308 (see Figs, 20 and 21) holds the lower end in place. This cover is curved, so water or cutting fluids may flow off which are used for flushing the tool for cutting or grinding operations, and to keep sprays of such uids from striking the contacts of the tracer. The tracer contacts are cooled and kept clean, by the screened air led through flexible tube 206 and cylindrical chamber 300 through slots 299 to said contacts.

A counterbalancing device is used for balancing the overweight of large and heavy tracer points against the weight of the shank 240, using the universal joint as a fulcrum. The sliding pin 24| has its inner end resting on shank 240 while its outer end is held by lever 242, pin 243, adjusting screw 244, and spring 246 for balancing, indicated by tongues 245-245'.

The wiring diagram (Fig. 28) will now be described in connection with some tracer details and connections. The frame 205 has a bore 261 through which the plunger rod 254 passes, and operates on pivot 268, the angle 258 thereby pushing the tracing contact 203 over to the (from work) contact 285 connecting by wire H3 to the (from work) controller C2, thereby pulling the tool carriage With tracer and cutting tool away from pattern and work, until the pressure of the pattern 405 against the tracer 230 is released. Then the tracing contact is again pushed over to the (to work) Contact 284 connected by wire to the lto Work) controller C! which in turn pushes the tool carriage with tracer and cutting tool toward pattern and work. These actions take place at the rapid rate of 60 times a second and are interspersed with 60 brake actions a second. These brake actions are always effective cn said brake S, but not on the tracing contact 283, because the pressure of the pattern against the tracer may be greater than the pull of the magnet 212 pulling the ball 210 into its cone socket 21| and thereby neutralizing the pressure of the tracing contact 283 when the pressure of the pattern against the tracer is released, as when the surface of the pattern is straight or has very little pitch.

The power line wires 3|4-3I5 with control A switch 3!1 are usually located on the general switchboard of the machine and supply 220 volt direct electric current by wire |90 to the brush |86 and supply flange |80' of current breaker K. Thence the rapidly interrupted current is led off the breaker disk |84 and brush |88 and wire I9! to tracing wire 290, leading to the tracing contact 283 being pushed over to the (to work) contact 284 by spring 483, and connecting with wire to the (to work) controller Cl, which completes the circuit to its magnets by the direct wire ll2 connecting with the direct line wire 3|4. When the tracing contact 283 is pushed by the contact of the pattern to the tracer as stated to the (to Work) contact 285 connected by wire I |3 to (from work) controller C2 the circuit is completed by direct wire ||4 to direct line 3|4.

The brake circuit of rapidly interrupted current leads off from breaker disk |85, by brush |31 and wires |89 and |45 to brake S and operates its magnets by completing the circuit to direct line 3|4, by wire |44, The magnet 212 of tracer T operating in conjunction with the brake S, leads oi from the brake current by wire 215 to its coil 213 and completes the circuit by wire 214 to the direct line 3|4. 'Ihe magnet 219 of tracer T operating in conjunction with the controllers CI-CZ leads off by wire 211, connecting to coils 280 in parallel, and completing the circuit by leads and Wire 216 to direct line Wire 3|4.

From work contact 265 is yieldingly connected to contacts 286-286 by insulation plug 285 sliding through the bore of contact 286', but held by pressure of spring 289 passed over shank 289', and held in tension by clip 292 held in adjusted position by screw 292.

A separate circuit of the interrupted current from the breaker disk |84 is connected by wire 3 2 to contact 286' and thence by wire 3 I 3, shank 289 and wire 3|6 to solenoid coil 330, operating the pressure bar 328 by magnet 334, and completing its circuit by wire 3|8 leading to the direct Wire 3|4. This circuit is for the purpose of stopping the work support long enough to let the tracer have time to extract itself from a very deep and comparatively straight up section of the pattern, by opening said normally closed contacts 285-286', thus releasing the pull of magnet 334 and the pressure on bar 328, which operates the friction drive D for the work support W.

Figs. 29 and 30 show a modified form of drive D for the work support W comprising a driving magnet 344 running like a loose pulley on shaft 353 of bearing bracket 351 having end bearings for said shaft 345-349, said bearing bracket oscillating on pivot 358 operated by bar 329, thus engaging either friction wheels 35| or 352 driving the Work support in one direction or reversing it to the opposite direction. In either case the circuit of wires 3|3-346 stays closed and the coil 356 operates the magnet 344 by means of brushes and collector rings 3|3-346. The circuit of magnetic flux extends through either one .friction pulley 35| or the other 352, as shown by arrows g-h. However, if said drive is used by closing the switches 341-348, then the solenoid 336 is not needed and is disconnected. The belt 359 is the same as used in the drive D shown in Figs. 1, 2, 3 and 4.

The variable speed drive D (see said above iigures) for driving the work support W is mounted on the platform 36|) and has the function to drive said work support in the greatest variety of speeds varying according to cutting or grinding operations and the various materials to be worked; it must reverse quickly, and stop when the tracer reaches a deep place to give time to release the tracer while the cutter keeps on cutting the material. The bearing bracket 318 is movably supported by said platform 360, to which it is held in pivotal sliding position by bolts 364 passing through slots 365 and turning on pivot 358 passing through a reinforced section, forming the Welding joint of bar 329 to the supporting plate 360 in which bolts 364 are firmly mounted for coupling bearing bracket 310 in sliding position with said supporting plate 360 and pushing bar 329 into the respective positions shown in dotted lines in Fig. 4, about the pivot 358, which is firmly screwed in the supporting platform 360 having `circular slots 305 in which said bracket 310 moves in the direction of arrows 355', thereby bringing the friction disk 355 in contact with friction wheel 35| and moving the work table 438 in the direction of arrow 3 (see Fig. 3) while the hand lever 4| Il is in dotted position 4|0". When pushed over to dotted position 4|U, the friction disk 355 engages the friction wheel 3527 and the work table 438 moves in the direction of arrowv 4. Said friction wheels are covered with a suitable friction surface 35| (see Figs. 2, 29 and 30). The motor 383 may be driven with any suitable current, the small sheave 382 driving pulley 33| keyed to shaft 35| and driving friction disk 355 also keyed thereto, and always running in the same direction.

The motor 445 shown in Fig. is a modification of motor 353 and has a loose pulley 4|5 combined with a disk armature, and driven by vmagnet 4|9 tight on the motor shaft, whose coil is connected by suitable collector rings and brushes to leads 3|2-3l3 and to wires 3|3-3l4. The said motor takes the place of solenoid 333 for stopping the work table 408 when the tracer is in a deep depression as stated. The friction 'disks 35|-352 are splined to shaft 350 and are jointly adjustable thereon by the rightand left handed screw 388 (see Fig. 1). Matching right and left handed tapped sleeves ,of guides 356-381 guide said friction wheels jointly along the shaft 350 inwardly for slower speeds and outwardly for faster speeds by turning crank handle 339 in either one direction or reverse thereto, thus being able to make very fine adjustments of feeding speed for the work table 408. The shaft 350 has bearing brackets 313 in which it runs, and the sleeve 31| is mounted thereto to drive sheave 38|] by belt 312. The sleeve 38| running on stub shaft 385 has the sheaves 385-352 and 383 in unison therewith.

The table 403 has end bearings 335 in which the lead screw 393 runs, and is pulling the said table by leading through the stationary nut 393 in opposite directions by the bevel gear and pinion connection housed in casing 390, the bevel pinion being driven by the double sheave 382- 383 and the belt 289. The yoke 314 has suitable bearings pivotally connecting it to both ends of shaft 358 with the outer part of the yoke terminating into a flat bracket, supporting bearing 318 in sliding adjustment against the edge 315 in slots 318 and being held in adjusted position for tightening belt 312 by bolts 319. An adjustable link 385-381 connects with its end bearings the stub shaft 385 and a shoulder turned on casing 390 as shown in Figs. l and 3, and is Set for tightening belt 289 by bolts 338 operating in suitable slots in said link sections. Said link in combination with yoke 314 also guides the said two belts in the up and down and in and out motions of the work support W and table 458. The pedestal 429 has sides 428 and beveled slides 421 on which the crosshead 435 is slidably retained by the beveled guides 423 in very accurate adjusted position by screw bolts 424 passing through suitable bores in lugs 423 and held in said adjusted position by check nuts 425 (see Figs. l and 3). The weight of the work support W is counterbalanced by weight 435 having a yoke 434 for attaching wire ropes 43| leading over rope sheaves 432-433 turning on studs.432'-433 with its free ends being fastened by eye bolts 430 to the crosshead 438. A cover 332 is provided to make gear casing 390 dustproof.

The work support W described above, has a vertical groove 429 for passing the nut 399 (see Fig.

3), and on which it is fed up and down on the pedestal 423 by actuating mechanism comprising lead screw 338 having bearings 333 at its upper and lower ends, a sprocket 333 attached to the screw, and a sprocket chain 455 leadingto sprocket 45| mounted on spindle 432 in adjustable bracket 404 for tightening said sprocket chain. The crank handle 453 having the usual square socket is passed over the upper extending square stub of spindle 452 for operating the work support up and down said pedestal 429 with a gradual feeding motion at the end of each cut when the table 408 is being reversed by the drive D. A suitable automatic feeding device (not shown) is inserted in the base and attached to the lower end of said lead screw 358, operating in conjunction with reversing bar 328 attached to hand lever 4||J by pivot 4I5. When said lever is moved in base B upon pivot 459, it cooperates with a semi-circular plate 4|2 having a stop notch 4| 3 receiving the nose of the sliding bolt 4|| to hold the lever in a neutral position in which the work table 488 stands still, since the constantly running friction disk 355 is then held out of engagement with said friction disks 35|- 352.

The reversing bar 328 (see Fig. 4) being held in said neutral position, the roller 33| of lever 333 operating on pivot 335 is held at the point 330 of the triangular shaped lock 333 welded to reversing bar 328, and the dotted position 333 shows said bar and lock moved forward and the roller 33| turning on pivot 332 in position for locking the reversing bar 328, thereby holding the running friction disk 355 in contact with friction disk 352 and moving the work table 438 in the direction of arrow 3, while in reversed direction of said bar and lock as shown in dotted position 33D" the table 488 moves in the direction of arrow 4. However, the solenoid 338, together with spring 338, supplies a flexible yielding pressure to said lock 330 by their combined pull on extension 340 by plunger 34| attached thereto by Divot 34|', all operating on pivot 333 suitably attached to the base of the machine. Said solenoid 335 is pivotally mounted thereto and held in position by casing 331. While the spring 338 keeps the related parts in position, the solenoid, by means of the current connection flowing through the customary closed contacts 286-286' of the tracer T, supplies the required pull against the respective bevel face of lock 338 to feed the table 458 as described. However, if the tracer strikes a deep spot in the pattern and the pressure of the pattern against the tracer 235 becomes excessive, then Contact 285 yields and thereby opens the contacts 283-285', thus slowing up or stopping said table 403. The tapering sides of lock 330 accommodate the differing angle of contact of the friction disk 355 to friction disks 35|-352 as they are nearer to the center of friction disk 355 when that angle is greater, or if they are further out, when that angle is lesser, the position of the small roller against said tapering sides of lock 330 Varies, but maintains a constant pressure for the friction contact of said friction disks.

The motor 440 (see Fig. 5) is a modification for accomplishing the same purpose by stopping the motor pulley 4|0 while the motor keeps on running. Also, the Amodification shown in Figs. 29 and 30 accomplishes the same result by releasing the magnet 344 for driving the friction disk 355. All other functions of said modified forms remain the same as in drive D.

An automatic reversing device for driving the table 408 has the upright feeding shaft 416 with a dog 411 splined thereto for up and down motion" on said shaft, while its free end is operated by the adjustable dogs 418 mounted with screws on the upper edge of the table 458, said feeding shaft being held in suitable lugs on the pedestal 429 and crosshead 43D. Below the table B said shaft operates the reversing bar 328 by the dog 419 striking pins 480. A modification thereto is shown in Fig. 6, showing an automatic operation of the reversing bar 328 by two solenoid magnets 325-326 operating the respective plungers 325-326' mounted on lug 321 of reversing bar 328, which is again shown in neutral position, as in Fig. 3. The leads 3|9 jointly connect to wire 3|5 and the leads 32|-322 lead by way of the reversing switch 323, to solenoid 325 as shown, moving the reversing bar in the direction of arrow K. When the dogs 418 throw the reversing switch, aided by spring 324, the table 408 will move in the opposite direction (see 'wiring diagram Fig. 28)

The base B is divided into two principal sections, being divided by the reinforced partition wall 448, which is bearing the weight of the upper construction by supporting the table B and is making the front section of said base a separated dustproof chamber having outer intake screen 436 covered with suitable dustproof fabric 438 separating the coarse dust. An inner second Vscreening cloth 422 is drawn over steel rods 44| inserted into suitable holes in sections of the side walls of said base B, thus forming an inner dustproof chamber 444, having an outlet 445, from which the air pipe 446 leads to the intake 456 of fan 46D. The motor 458 has pulley 453 connected to the fan pulley 455 by belt 454 running in the direction of arrow w, sucking the air through said screen 442 and screen sections 443, the screened air leading in the direction of arrows y', and the arrows r and v leading from said fan in pipes 451 into the control set E for cooling the same, and through pipe 458 to the current breaker K and the tracer T by means of flexible tube 286. pulley 452 connected to pulley 459 of drive shaft |51 by belt 463 leading in the direction of arrow u. A step cone 225 mounted on said shaft is connected to step cone 224 by belt 226 for driving the current breaker K in the direction of arrow l. rI'he motor 45D, fan 460, and connected accessories are mounted in chamber 449 of base B and is closed in by dustproof sheathing 441 (see Fig. 1). A small chamber 461 is provided above said table B', having a cover 465 with passage 465 for the flexible tracer cable 464 passing therethrough and forming the loop 466, allowing for various settings of the tracer and for blocking it up on the tool carriage when long and narrow pieces of pattern and stock are set above each other on said table 408, when said loop is pulled out to reach said higher position of the tracer. A wiring panel 461 is provided receiving all of the tracer wiring from the tracer cable 464 on suitable wiring posts and leading from there to the current breaker, controllers, brake, etc., as specified in Fig. 28.

An important feature in the construction of the controllers CI and C2 is the use of a series of small magnets set in ring-like form, near the outer rim of said controllers, so that said controllers may readily be made more powerful by simply increasing their diameter and adding the required number of additional small magnets Said motor 450 has a second L wthereto. Likewise, said controllers can readily be made smaller by using only about three or four of said magnets, when the controllers are used with different gearing for controlling the tracer and tool by means of a lead screw, while in either case their eiciency remains the same. The small coils 58 are inexpensive and easily replaced or exchanged for weaker or stronger ones, according to the particular uses for different ma- 10, chnes. The brake S being of very similar construction, and using the same small magnets, can be changed in size in like fashion, so that said control sets E can be made for any size machine and any purpose without fundamental changes. When a very small control set is used, the transmitter 5| is replaced by a long pinion, preferably of one piece with the control shaft The modifications shown and described are for the purpose of alternate use for various materials and working conditions on the same machine, and do not change the nature or principles of my invention.

The electric control system herein disclosed is useful Wherever a minutely accurate control is required to be achieved electrically from a remote point. In an electrical steering gear in fioor leveling devices, for elevators, and in many other pieces of apparatus, there is a tendency for the device which is being operated t0 overrun the electrical control. In the present invention in which the use of a brake alternates so rapidly with the use of the feed, it is almost impossible for the actuated device to overrun. There is another advantage in that the frequent interruption of the current by the rotary switch relieves the control switch of all tendencyto arc,thus eliminating relays and the like.

The general arrangement by which the tool is driven at a variety of speeds without loading the carriage is important to the sensitive and deli- --,`cate operation of a device of this character. It --will be noted that several speeds are provided between the driving motor 38 and the countershaft 22, and additional driving speeds are provai vided between the countershaft and the tool A spindle, Particularly, however, it is to be noted that the drive to the spindle is eifective from a pulley sufciently elongated so that no connection to the spindle is necessary other than that '50 of the belt itself, the weight of which is carried from above.

One of the purposes of the invention is to provide for eifecting maximum accuracy of controlled movement and of controlled positioning of the driven mechanism under the control of the tracer and generally to improve the construction and operation of such mechanism. In a tracing machine maximum accuracy in reproducing the form of the pattern on the work piece requires a minimum of over-al1 lag or response-time for starting, stopping or reversing the support or slide which carries the tracer and tool, for example. The slide should instantly follow the control of the tracer device, and to this end the control clutch mechanism is required to instantly interpret and transmit to the slide the movement of the tracer stylus, as reflected in the positioning of the tracer contacts.

One of the improvements contributing to the general purposes mentioned is to effect continuous rapid vibration of the active clutch or brake parts of the driving and braking mechanism. Among other improved results effected by the vibration is to reduce the delay or lag in controlresponse such as otherwise might occur through the increased friction resisting movement of parts from a position of rest.

The clutch-brake mechanism of `the present disclosure provides several different vibratory effects, as follows:

Referring to Figs. lil-11, the spring pressed pivoted levers 85, which may be associated both with the driven clutches and with the brake, carry shoes 85 of material, such as soft iron, which v carries some of the flux of the associated magnet cores 58 whenever the associated vibrator pressure rings 'l5 are magnetized for effecting friction pressure on the associated clutch or brake driven members. ous relatively slight pressure of the levers on the rings and of the rings on the associated driven friction members, for purposes later mentioned, but the relationship of the parts is such that the periodic magnetizing and vdemagnetizing of the magnet cores by the interrupted current as has been described, which occurs continuously in the brake magnets, and occurs in the magnets of each of the forward and reverse clutches continuously during the time that the tracer has selected the clutch for driving, effects a periodic pressure vibration of the pivoted levers 85 on plates 15, and of plates T5 on the associa-ted driven plates such as 55, whereby the effect occurs on both friction faces of the plates 55.

Referring to the modified structure of Figs. 8, 9 it will be seen that in this instance also the brake is vibrated as described, but the vibrator means is modified. The springs ISI continuously relatively lightly urge the pivoted levers in direction for the friction shoes |31 to set up pressure on the brake ring 51 and the continuous periodic energizing of the magnet coil 202 sets up the periodic vibration as before described. Further, each of the structures of the modified forms respectively shown in Figs. 7, 8 provides vibration effects at all times when either of the forward or reverse clutches is activated by the tracer control mechanism. The rapid periodic energizing of either of the clutches sets up a torsional pressure vibration in all the drivent parts connected for actuation of the tracer controlled support or slide. It is obvious that, as between the interconnected clutch and brake elements there exists a torsional deflection, reversed periodically by the alternate application of the driving and braking effects, previously described. Such reversal of torsion effect is transmitted to the tracer controlled slide as a vibratory force operating alternately in directions to move or stop the slide, and depending in part upon the mass of the slide and in part upon the frequency of the vibration forces, the result may be such as to effect either continuous vibratory advance movement or alternate start and stop of the slide. Also, by reason of the inertia and friction of the slide, such forces effect a torsional vibration in al1 of the rotation elements of the train connecting the clutch-brake device to the slide.

It will be noted that in each of the clutchbrake devices herein disclosed the opposed friction plates of each of the forward and reverse clutches and of the brake are continuously maintained in friction contact, without clearance. In the device of Figs. 10, 1l the result is effected by springs 8l, and in the modified device of Fig. 8 by the springs I3I. Such continuous pressure contact of the parts is important for effecting the minimum of over-all lag and response time, and also is of assistance in rendering effective the The springs 81 maintain a continuvibratory effects, particularly in the driven transmission elements and driven slide.

In each of the clutch forms the clutch or brake friction elements which are connected to the driven portion of the transmission are each located between friction plates which are relatively movable toward one another to effect friction Contact on `both faces of the intervening driven element, which is particularly effective both for increasing the driving or retarding capacity, as the case may be, 'and also where the device is to be continuously operated Without clearance, in the latter instance because effective continuous contact can be maintained with considerably less pressure per unit of friction surface area.

I claim:

l. An electric control device comprising the combination with driving and driven members, ofelectrically energized means for controlling the transmission of motion from the driving to the driven member, a brake applicable to said member, means for automatically applying said brake intermittently to said driven member and intermittently rendering said brake inoperative -thereon, and current flow controlled means for energizing said electrically energized means intermittently during the interval when the brake is inoperative.

2. An electrical control device comprising the combination with a driven member, of driving means for said member and .braking means for said member, electrically energized control mechanismsI for actuating said driving and braking means, electrical connections leading to the respective control mechanisms, and a current control means operatively connected for supplying current alternatively through said connections at frequent intervals, whereby to actuate said driving and braking means alternately and at frequent intervals.

3. A control device comprising driving and driven members, clutch means for connecting said members, brake means operable upon the driven member, means for intermittently operating the brake means to urge a stop of the driven member at short intervals, and mechanism for actuating the clutch means to drive the driven member from the driving member at intervening intervals.

4. A control device comprising the combination with a driven member, of forward propelling means, rearward `propelling means, and braking means operable upon said member, means for continuously and automatically rendering said braking means eective at short intervals upon said member, means for rendering one of said propelling means effective upon said member in timed relation to said braking means and during the interval when said braking means is inoperative, and a control device operatively connected with said propelling means to determine which thereof shall be operative upon said member during such intervals.

5. For an electric tool control, a control device comprising stationary and moving electromagnetic elements, means for intermittently energizing one of said elements periodically at a predetermined frequency, a tracer, a tool feed device including an actuating armature in operative relation to said elements and stopped or advanced according as it is attracted by one or the other of said elements and means including electric contacts and connections controlled by said tracer for directing current t0 and from another of said elements.

6. The combination with a tracer and carriage, of feeding mechanism therefor including a driving part, a driven part connected with the carriage, and electromagnetic clutch effective between said parts and an electromagnetic brake means for stopping said carriage, means for intermittently energizing the brake, and means controlled by said tracer for intermittently energizing the clutch, said brake and clutch ener-gizing means being alternatively operative.

'7. For an electric tool control, a control set comprising a carriage, a tracer and tool mounted on said carriage for movement to and from pattern and work, an actuating member for said carriage, a forward driving electromagnetic clutch element, a rearward driving electromagnetic clutch element, and an electromagnetic brake element respectively adapted for control of actuation of said member, means for continuously driving said clutch elements in opposite directions, current supply means operatively connectible to energize said clutch elements and brake element alternately and intermittently at high frequency, and means actuated by said tracer for regulating the operation of some of said elements.

8. An electric tool control comprising a carriage, a tracer and cutting tool mounted on the carriage lfor movement therewith, oppositely moving propelling elements, a driven element, electrically controlled means for selectively coupling the driven element to either of said propelling elements, brake means intermittently effective upon said driven element, and tracer controlled means operative only in the interval of brake inaction for enabling the coupling of said driven element selectively with one of said pro-- pelling elements.

9. A control device comprising a driven member, electrical means for controlling the operation of said member including electrically controlled driving connections and electrically controlled braking connections, a circuit to said driving connections including a switch, a second circuit to said braking connections, and means for supplying a periodically interrupted current alternately to the respective circuits, whereby to energize said braking and driving connections alternately.

l0. In an electric tool control, the combination with a tracer and switch means closed by the tracer upon its deflection from an intermediate position, impositive means periodically inoperative for automatically drawing said tracer toward said intermediate position, and means for intermittently applying power to said impositive means for rendering it operative.

1l. In an electric tool control, the combination with a tracer, switch means closed by the tracer upon its deflection from an intermediate position, a driven member, electrically controlled driving means therefor, electrically controlled braking means therefor, and means for alternately energizing said driving and braking means, said switch controlling the energization of said driving means only, and means whereby the energization of said braking means tends to restore said tracer to said intermediate position.

12. The combination with a machine having a relatively movable work support and cutting tool, of a combined speed changer and reverser operatively connected to effect relative movement between said support and tool and comprising driving and driven shafts mounted for relative angular movement and having an intermediate relative position substantially at right angles to each other, friction disks spaced upon one of said shafts at each side of the end of the other shaft, a complementary friction disk carried by said other shaft and engageable with either of said first mentioned disks upon the occurrence of relative angular movement between said shafts, and means for adjusting said first mentioned disks to and from each other axially from the shaft upon which they are mounted 13. The combination with a'guideway comprising a pair of rails having spaced longitudinally grooved surfaces, of a slide having a portion interposed between said surfaces and provided with complementary longitudinal grooves, a set of antifriction bearings confined in the respective grooves of the slide and the rails, whereby to provide support for the longitudinal movement of said slide portion between said rails and stop means connected With saidv rails in the path of said bearings for limiting the movement of said Vbearings independently of said slide.

14. In a diesinking or copying machine, the

combination with a Work support, of a tool slide carrying a tracer and cutting tool and movable to and from said support, guide rails for said slide having laterally spaced longitudinal grooves, portions between which a portion of said slide has complementary grooves, balls positioned in the respective grooves of the slide and rails, spacing plates for said balls interposed between the respective rails and the slide and apertured to receive the several balls, and means adjustably limiting the movement of the respective plates, whereby to fix the range of ball movement in the several positions of the slide.

15. A device of the character described, comprising the combination with a work support and feed mechanism therefor, of a continuously operable source of power for said mechanism, disengageable means for driving said feed mechanism from said source of power, a tracer carriage movable to and from said support, a tracer and tool upon said carriage, means actuated by the tracer for regulating the movement of the carriage, and means effective upon the overloading of the tracer for disengaging said driving means to interrupt the drive to said workY support.

16. In a device of the character described, the combination with a contact frame and a switch controlled in the movement of said frame, of a universally mounted tracer point, and means for actuating said lframe in a switch closing direction upon the occurrence of any oscillatory movement of said tracer point, said means comprising a lever connected with the tracer .point and having a socketed end, `a push rod connected with the :frame and having a socketed end, and at least one ball interposed between the sockets of said lever and push rod.

17.. In a device of the character described, the combination with a switch and a pivoted switch actuator, of a lever adjustable along said actuator to en-gage different portions thereof for operating said switch with greater or less movement in; `.proportion to the movement of said lever, a push rod engageable with said lever, a tracer point mounted for universal and yielding movement and provided with a socketed lever, and at least one ball interposed between the end of said socketed lever and said push rod.

18. In a device of the character described, the combination with a universally and yieldably mounted tracer lever, off a tracing point carried thereby, means operable by said lever for closing a switch, and means operative upon said lever for counterbalancing the weight of said point, said means comprising a postl extending upwardly from said lever, a counterbalancing lever engaging said post, and means biasing said lever adjustably to oppose the Weight of said point.

19. fn a device of the character described, the combination with a slide, an operating shaft therefor provided with stationary bearings, and means for rotating said shaft in both directions, flexible means encircling said shaft and extending in opposite directions therefrom to said slide, and means adjustably tensioning said means with respect to said slide, whereby to eliminate lost motion and ensure accurate operation of said slide to and fro in accordance with the rotation of said shaft.

20. In an electric tracer, the combination with an apertured control member subject to displacement, of a yball in the aperture, and an electromagnet having a pole upon which the ball is movable, and means `for energizing said electromagnet from time to time, whereby the attraction thereof for the ball will tend to center said control member in a predetermined position.

21. In an electric tool control, the combination with a tracer mounted for yielding movement from a predetermined central position and `provided with contact means, of stationary contact means enga-geable by said tracer contact means upon the yielding movement of said tracer, and means operable intermittently at high frequency for restoring said tracer to said predetermined position whereby periodically to assure the separation of said contact means.

22. In a device of the character described, the combination with a tracer yieldably movable from a predetermined position and provided with contact means, of stationary contact means engageable by said tracer contact means upon the yielding of said tracer from said position, a tool and tool support mounted for movement, electrically controlled means for regulating the movement of said tool and tool support, a circuit including said electrically controlled means and said contacts, means for periodically opening said circuit, and means for automatically restoring said tracer to said predetermined position upon each interruption of said circuit.

23. In a device of the .character described, .a tracer biased for movement toward a predetermined position and yieldable therefrom, an electromagnet arranged to supplement the bias of said tracer toward said predetermined position, contact means closed by the movement of said tracer from said position, and circuit means for periodically energizing said electromagnet.

24.,In a device of the character described, a tracer biased for movement toward a predetermined position and yieldable therefrom, an electromagnet arranged to supplement the bias of said tracer toward said predetermined position, contact means closed by the movement of said tracer from said position, and circuit means for periodically energizing said electromagnet, together with circuit means for alternately energizing said contact means, whereby the circuit to said contact means is interrupted at the time said electromagnet is energized.

25. The combination with a machine having a relatively movable work support and cutting tool, of acombined speed changer and reverser operatively .connected to effect relative movement between said support and tool and comprising a driven shaft having xed bearings, a

4driving shaft mounted for relative angular movement respecting said driven shaft to and from an intermediate position wherein said shafts are substantially at right angles, a friction disk upon the driving shaft, .and friction disks upon the driven shaft spaced at each side of the axis of the driving shaft for engagement with the face of the rfriction disk carried by the driving shaft, and means connecting said driven shaft with said work support.

26. The combination with a machine having a relatively movable work support and cutting tool,

of a combined speed changer and reverser operatively connected to effect relative movement between sai-d support and tool and comprising driving and driven shafts mounted for relative angular movement and having an intermediate rrelative position substantially at right angles to each other, friction disks spaced upon one of the shafts at each side of the end of the other shaft, a complementary friction disk carried by said other shaft and engageable with either of the first mentioned disks upon the occurrence of relative angular movement between said shafts, means for adjusting said rst mentioned disks concurrently to and from each other axially along the shaft upon which they are mounted, whereby to vary the driving relation between said shafts, means for adjusting the angularity of said shafts with respect to each other, whereby to engage one or the other of said first mentioned disks with said complementary disk, and means biasing said shaft adjusting means toward one or the other extreme of its position whereby yieldably to maintain said Idisks in engagement, said biasing means including a spring, a cam and a cam follower arranged for the variab-le tensioning of said spring according to the angular disposition of said shafts, whereby to vary the pressure engagement of said disks according to their displacement.

27. The combination with a tracer and contact points controlled thereby, of means for intermittently energizing said contact points, and electromagnetic means for urging said contact points to close, said electromagnetic means being connected to said contact energizing means, whereby to be intermittently energized concurrently with the energization of said contacts.

28. The combination with a tracer and a carriage upon which the tracer is mounted, of driving connections for said carriage including a feed clutch, means controlled by said tracer for activating said feed clutch in a predetermined position of said tracer, said clutch activating means being intermittently operable, and supplemental means connected with said activating means and intermittently energized concurrently therewith for urging said tracer periodically toward said position.

29. The combination with a tracer and a carriage controlled thereby, said tracer being provided with a mounting upon which it is yieldable between a plurality of positions thereon, of driving connections to said carriage provide-d with clutch and brake mechanisms, means for intermittently energizing said clutch mechanism subject to the control of said tracer, means for intermittently and alternately energizing the ybrake mechanism, means whereby said tracer in one of its positions effects the energization of the clutch mechanism and in another of said tracer positions precludes the operation of said clutch mechanism, and a biasing device connected with the means which intermittently energizes said clutch mechanism for drawing said tracer toward the position in which said clutch mechanism is rendered effective.

30, The combination with a tracer, a carriage and driving connections to the carriage including a clutch and brake, of meanscontrolled by the tracer for rendering said clutch effective in one tracer position and ineffective in another, a plurality of opposing biasing devices operatively energizable to act alternately upon said tracer to assist its movement to the respective positions, and means for alternately energizing said brake and clutch and concurrently energizing the respective devices, the energlzation of the clutch being concurrent with the energization of the biasing device which urges the tracer toward the position in which said clutch is rendered effective.

31. The method of controlling a driveable member to prevent overrun which comprises :braking said member for brief intervals and with high frequency, the synchronous application of power urging motion of said member between certain intervals of braking thereof, and the control vof such power application in accordance with the desired advance of said member whereby said member is urged to advance only between certain intervals of braking and not between other intervals of braking.

32. The combination with a tracer mounted for yielding movement between two positions and means biasing said tracer for movement toward one of said positions, of a carriage operatively connected to be controlled by said tracer and provided with driving connections including a clutch and a brake, means for intermittently supplying power for the energization of said clutch, and means controlled by said tracer in its last mentioned position for rendering said power effective upon said clutch, together with means for applying said brake intermittently when said clutch is de-energized.

33. A device of the character described, comprising the combination with a work support and a cutter support, of means mounting the respective supports for relative movement to and from each other and for relative movement transversely with respect to each other, a traverse mechanism operatively connected with one of said supports for movin-g it transversely with respect to the other, a feed mechanism connected with one of said supports for moving it in a direction to and from the other support, a cutter operatively mounted upon the cutter support to partake of the relative transverse movement of the motion to and from the work support, a tracer operatively mounted on the cutter support and provided with control means for interrupting motion transmission through said feed mechanism, said control means comprising a first part connected with the tracer to partake of the movement thereof and a second part in the path of the first part to be engaged thereby under the influence of the tracer, a resiliently yieldable mounting for said second part, and a second control means connected with said mounting to be actuated upon the yielding thereof and provided with connections for the interruption of motion transmission through said traverse mechanism, whereby to stop the transverse relative movement of the respective supports upon the overloading of the tracer.

34. In a copying machine, the combination of a work support and a tool support, transmission mechanism for relative movement of said supports including interruptible driving clutch means and engageable and disengageable motion restraining means, and control means for said transmission mechanism including means connectible for rapidly continuously repeated alternative interruption and connection of said clutch means, a pattern controlled tracer device determinative of connection or disconnection of said connectible means, and overrun preventing means automatically operable during the tracer controlled connection of said connectible means for engaging said restraining means during the intervals of said rapidly repeated interruption of said clutch means.

35. A machine as specified in claim 34 in which said connectible means and said overrun preventing means are each electromagnetic, said machine including a source of rapidly repeated current impulses and said control means operating to supply alternate current impulses from said source respectively to said connectible means and to Said overrun preventing means during said tracer controlled connection of the connectible means.

36. In a copying machine, the combination of a work support and a tool support, transmission mechanism for relative movement of said supports including an interruptible driver, and control means for said transmission including a tracer device providing elements relatively shiftable under the control of la pattern to different positions respectively effecting interruption and driving operation of said driver, and vibrator means connected for rapidly and continuously alternately urging said different positions of the elements.

37. A machine as specified in claim 35 in which said vibrator means is electromagnetic.

38. In a copying machine, the combination of a work support and a tool support, transmission mechanism for relative movement of said supports including an interruptible driver, and control means for said transmission inbluding a tracer device providing elements relatively shiftable under the control of a pattern to different positions respectively eifecting interruption and driving operation of said driver, means continuously urging said elements to said driving position thereof, and vibrator means connected for rapidly continuously alternately urgingsaid elements to said interruption position and releasing said elements for movement to the other position.

39. In a copying machine, the combination of a work support and a tool support, transmission mechanism for relative movement of said supports including an interruptible driver, and control means for said transmission including a tracer device providing elements relatively shiftable under the control of a pattern to different positions respectively effecting interruption and driving operation of said driver, and an actuator device rapidly intermittently urging said elements to said position effecting interruption.

40. In a copying machine the combination of a tracer support and a pattern support, transmission mechanism for relative movement of said supports including a driver device energizable and deenergizable for controlling a forward direction of one of said supports toward the other, and control means for said transmission including a tracer device carried by said tracer support and providing elements movable to first and second relative positions respectively for effecting said energized and deenergized conditions of said driver device, power vibrator means rapidly al- 

